Image broadcasting system



May 21, 1935. w. G. H. FINCH 19,575

IMAGE BROADCASTING SYSTEM Original Filed March 26, 1934 10 Sheets-Sheet l RECTIFIER RECE'VER INVENTOR WILLIA G. H. FINCH.

ZLZ W ATTORNEY y 1935. w. s. H. FINCH IMAGE BROADCASTING SYSTEM Original Filed March 26, 1934 10 Sheets-Sheet 2 INVENTOR WILLIAM GH. F'INCH. A

ATTORNEY May 21, 1935. w H, FINCH IMAGE BROADCASTING SYSTEM Original Filed March 26, 1934 10 Sheets-Sheet 5 INVENTOR LUAM G. H. F'INCH. P4 3.4 W

ATTO R N EY May 21, 1935. w. e. H. FINCH IMAGE BROADCASTING SYSTEM 10 Sheets-Sheet 4 Original Filed March 26, 1934 Hiiiiiiiiiiiiiiiiis WILLIAM G H. FINCH.

ATTORN EY y 1935. w. s. H. FINCH IMAGE BROADCASTING SYSTEM Original Filed March 26, I934 10 Sheets-Sheet 5 INVENTOR WILLIAM G. H. FINCH.

ATTORNEY 3 May 21, 1935.

w. G. H. FINCH Re. 19,575 IMAGE BROADCASTING SYSTEM Original Filed March 26, 1934 10 Sheets-Sheet 6 INVENTOR LLIAM G. H. FiNCH.

ATTORNEY y 1, 1935. w. G. H. FINCH Re. 19,575

IMAGE BROADCASTING SYSTEM Original Filed March 26, 1954 10 Sheets-Sheet 7 fllllllllllllllllllllllllllllll r i I 1 I //29 m I 0 1L /3/ O T" INVENTOR WILLIAM G. H. FINCH.

ATTORNEY 10 Sheets-Sheet 8 INVENTOR WILLIAM G.H. F-INCH.

ATTORNEY May 21, 1935. w. cs. H. FINCH IMAGE BROADCASTING SYSTEM Original Filed March 25, 1954 10 Sheets-Sheet 9 -IIMEHUU INVENTOR WILLIAM G. H. FINCH.

ATTO RN EY May 21, 1935. w F|NcH Re. 19,575

IMAGE BROADCASTING SYSTEM Original Filed March 26, 1934 1.0 Sheets-Sheet 10 v 1 INVENTOR (H2 flair WILLIAM G. H. FINCH.

ATTORNEY Reissued May 21, 1935 UNITED STATES PATENT OFFICE Serial No. 717,304, March 26, 1934.

Appllw tion for reissue March 23, 1985, Serial No.

47 Claims.

My invention relates to novel apparatus for and methods of transmitting signals and more particularly relates to novel apparatus for and methods of visual broadcasting.

In the transmission of facsimile signals it has heretofore been the practice to employ a cylindrical member on which the picture or object to be transmitted by facsimile was mounted. The cylinder was scanned by rotating the cylinder past a pointer and at the same time moving the cylinder with respect to the pointer in a longitudinal direction by means of a worm mounting. An electrical contactor mounted on a stylus was employed for detecting the light variations of the image on the cylinder.

The obvious defect of such a system was that it could transmit only the image mounted on the cylinder and was not adapted for the continuous transmission of messages.

For the purpose of transmitting any relatively long messages by facsimile, it has been proposed to oscillate an arm carrying a stylus over a. moving sheet on which the message which is to be transmitted by facsimile is recorded. In this type of arrangement no practical photoelectric cell arrangement which is operated in accordance with variations of the image for transmitting facsimile signals has heretofore been developed, nor has it been possible in the systems heretofore used to employ the same system and apparatus for the transmission either of black and white pictures or half tones, as desired.

Moreover, the mechanisms proposed were complicated, requiring many parts which were heavy and no practical construction has been suggested for facsimile transmission which would be adaptable for mobile use, as on automobiles, airplanes, ships and the like.

I have invented a novel adaptation of the photoelectric cell arrangement and simple synchronizing arrangement, requiring a mechanism light in weight, inexpensive and easy to operate for the broadcasting of images, the apparatus being operated either by wire or by radio.

A need has especially arisen for a mobile image broadcast receiver mounted on devices such as automobiles, buses, airplanes, sea vessels, etc. Heretofore it has been the practice to receive messages on such devices by telephone. This had the defect of being costly, leaving no record of the receipt of such message, and involving the human error in reception.

To overcome these defects, I have invented a mobile printer which makes a permanent record of the message received, is inexpensive and suiliclently light to be practical for mobile purposes. This forms the subject matter of my Patent 1,932,579, granted October 31, 1933 and my copending application 8. N. 695,740 filed October 31, 1933.

As a complement to the printer described in the patent and application referred to above, a receiver for the reception of broadcast images is also required. Heretofore, it has been found necessary to provide heavy, complicated and costly equipment for such reception. This retarded its more general use and made its use for mobile purposes practically out of question.

I have developed a receiver of broadcast images which is primarily inexpensive and light, so that it can be used as a mobile device for reception.

Accordingly, an object of my invention is to provide novel apparatus for and methods of transmitting pictures.

A further object of my invention is to provide novel methods of and apparatus for transmitting either black or white pictures, as desired.

Still a further object of my invention is to provide novel apparatus for and methods of synchrcnizing an image broadcasting system. 25

Another object of my invention is to provide a novel image broadcasting system which may be operated either by radio or by wire circuits.

Still a further object of my invention is to provide a novel construction of photoelectric cell. 30

Another object is to provide novel image broadcasting system operated by photoelectric cell.

Still a further object is to provide a novel mobile image broadcasting system adapted for use in automobiles, airplanes, ships and the like.

Still another object is to provide a simple, rugged image broadcasting receiver that may be operated directly from a radio receiver.

A further object is to provide novel synchronizing means whereby the same signal channel is employed for the image and the synchronizing signals. 7

In the operation of facsimile systems heretof cre, the rate at which words could be sent was so much lower than the rate of transmitting by telegraphy that the use of facsimile for such purposes has been impractical.

1 I have discovered that detail is not consequential in image transmission of words and that by a sacrifice of detail I can provide a word transmitting system operating at even higher speeds than now obtainable by telegraphy.

In accordance with my invention, I contemplate reducing the image to be transmitted a number of times to an image which is a small fraction in size of the original image; scanning this reduced image for transmission; receiving the image reduced: and thereafter enlarging it. In a modified form I contemplate operating the receiver scanner to produce a direct enlargement.

Accordingly a further object of my invention is to provide novel apparatus for and methods of broadcasting word images.

A further object of my invention is to provide novel apparatus for and methods of broadcasting images by reducing the sizes of the image to be broadcasted; receiving the reduced image; and enlarging it,

In one application of my system I contemplate employing the standard radio receiver now found in most homes, for the reception of broadcast images.

Heretofore it has been impossible to transmit messages for recording because the printers or facsimile receivers proposed were too expensive. large and cumbersome for home use.

I have discovered that with my novel broadcast image receiver it would now be possible for a newspaper to supply a news service by broadcasting illustrated news bulletins with my novel image broadcasting system. Connected in the output oi the usual radio receiver, it would be possible with my novel image receiver and recorder to receive and record such messages.

My invention contemplates that the owner of a radio receiver could, whenever he desires. switch the output of his receiver circuit to my image receiver for the reception of image or i'acsimile signals. Such a subscriber would, when he is about to turn off the radio at night, merely switch his circuit to the image recorder. During the night illustrated news bulletins, advertising, etc. would be transmitted and received on his radio receiver and in the morning would be available fully recorded.

In the present broadcast system, the programs are hampered by the inability to present a clear picture of the scene at the broadcasting studio, television still being a thing of the future. In accordance with my invention, each broadcast program could be preceded by or interspersed with a vision broadcast to provide the listener" with some picture of the scene from which the broadcast occurs.

Accordingly an object of my invention is to provide novel apparatus for and methods of broadcasting images in conjunction with present audible programs.

A further object of my invention is to provide novel apparatus for and methods of broadcasting and receiving illustrated news bulletins on a regular sound radio receiver.

Still a further object of my invention is to provide a novel image receiving apparatus having considerable flexibility and operable from a standard sound radio receiver.

There are other objects of my invention which, together with the foregoing, will appear in the detailed description which is to follow in connection with the drawings in which:

Figure 1 is a circuit diagram of the transmitter:

Figure 2 is a. circuit diagram of the receiver;

Figure 3 is a detailed view of the right hand side elevation of the transmitter;

Figure 4 is a cross section of the main shaft;

Figure 5 is a detailed drawing of the cam;

Figure 6 is a top view of the transmitter;

Figure 7 is a right hand side elevation of the receiver;

Figure 8 is a detailed view of synchronization mechanism;

Figure 9 is a left hand elevation of receiver;

Figure 10 is a top view of receiver;

Figure 11 is a detailed drawing of roller mechanism;

Figure 12 is a of the receiver;

Figure 13 is a detailed view of the receiving cam; diilgure 14 is a detailed view of the synchronous Figure 15 is the synchronous motor;

Figure 16 is a drawing showing a modification of the invention for the reception and transmission of half tone pictures;

Figure 17 is a modification of portion of the receiver showing an electrochemical method of reception;

Figure 18 is a modification of the receiver employgg an electrodynamic motor and arc-shaped n1 9figure 19 is a top view of Figure 18 taken at section through the main shaft Figure 20 is a side plan view of an airplane in which my novel receiver is mounted;

Figure 21 is a side elevation showing the details of mounting my receiver; and

Figure 22 is a cross section elevation taken at 22-22 of Figure 21.

Referring to Figure 1, I have shown a developed positive fllm or similar band I moving in the direction of the arrow at a predetermined speed controlled by synchronous single phase motor 2 in a manner to be described hereinafter. Motor 2 may be driven from a standard source such as a sixty or twenty-five cycle line. Upon film I, the image to be transmitted appears in black and for purposes of illustration, I have shown on Figure 1 an enlarged letter Y drawn in the middle of band I. In this case, the letter Y is to be transmitted. On one side of the film I, a relatively wide black line is drawn, which is shown at 3 in Figure l, for synchronizing purposes to be explained hereinafter.

Behind the picture bearing transparent band I, a photo-electric cell 4, shaped as a section of and connected to a oscillator of carrier frequencies modulated by the picture currents generated by the photoelectric cell as the image to be transmitted is scanned in a manner to be described hereinafter. For wire transmission, a similar arrangement or just an impulse transmitter may be used.

When the single phase motor 2 is set in motion by closing switch 5, its armature 6 revolves in the direction shown by the arrow and the worm mounted at I on the armature shaft meshes with and drives worm gear 8. Gear 8 is mounted on and rotates shaft 9 in the direction of the arrow.

Shaft 9 carries secured thereto a cam I0 which, in revolving, causes cam follower 52. carrying an image scanning device II, pivoted at I2, to oscillate. Cam follower 52' scans the photograph appearing on band I.

For puropses of simplicity, the mechanism which steps the pho ographic band I forward is not shown in this figure (to be described in conmore nection with Figure 3), but atthe completion of each cycleof scanning arm H, the picture containing film is fed forward a predetermined amount. depending upon the quality of the picture desired, so that on each swing of arm Ii, a newlineofimagepointsisscanned. Allofthis will be shown and described in greater detail hereinafter. It will now be clear that as motor 2 rotates, arm ll oscillates in a sweeping movement back and forth over the picture to be transmitted and at the completion of every oscillation. a difl'erent line of the picture to be transmitted is scanned.

A suitable lighting system comprising a source of light of constant intensity, an objective lens and a reflector, capable of bending the light beam degrees, is focused through the picture upon the photoelectric cell C. It will be clear that whenever a dark or black portion of the image to be transmitted lnterposes the light beam between its source and the photoelectric cell 4, a variation in the current generated by the photoelectric cell in its circuit occurs. In the case of black and white transmission, only two current variations are produced. For transmitting shades between black and white a corresponding number of current variations result. In half tone transmission it would be necessary to break up the picture into sections in the manner well known in the art.

When these current variations are amplified and applied to the transmitting equipment, they will be radiated through the air or transmitted by wire to the receiving circuit and related apparatus shown diagrammatically in Figure 2.

Referring now to the receiving circuits shown schematically in Figure 2, a synchronous single phase motor is set in motion by closing the local circuit switch II. This motor is preferably driven from a source of alternating current tied into the system supplying power to the transmitting motor 2. These two motors are thus driven in synchronism. To the armature of motor [3 is secured a worm I5 suitably mounted in bearings and driving gear I6, secured to shaft IT, in the direction indicated by the arrow. A synchronization disc it, free to rotate about shaft I1, is located so that a pawl i9, under the action of spring 20, normally engages ratchet wheel 2|, which is securely fastened to shaft II. The synchronization disc I8 is secured to the hollow shaft 22 which is shown diagrammatically for simplicity at right angles from disc I 8. Upon the hollow shaft 22 is secured a cam 23, shaped substantially like cam H) in Figure l, which in turn actuates cam follower arm 24, pivoted at 25, causing stylus 90 to oscillate back and forth over a suitable image retainer shown at 26, which travels in the direction of the arrow at a predetermined speed under control of motor l3.

The cam follower 24 actuates an arm 89 upon which is pivoted at 35 the stylus 90, the end of which is forked as at 24' and supplied with an arcuate iron armature 21 to cooperate with the pole pieces of a polarized magnet 28 having windlugs 29. When the magnet winding 29 is deenergized, the pole pieces act upon the armature 21 to hold the marker carried by stylus 90 out of contact with the signal recording band 26. When magnet winding 28 is energized by a signal, the armature 21 moves upwardly and causes stylus 90 to rotate about pivot 36 and thereby cause marker 93 to record the signal on band 26. By pivoting stylus 90 on the oscillating arm 89, a signal may be recorded by a mark corresponding to said signalatanypositionofsaidarmas it sweeps from side to side of its path of movement. 7

When switch II is closed. motor I; is set in motion, thus imparting an oscillatory movement to stylus arm 90, said movement being in unison with the motion of arm H of the transmitter shown in Figure 1. so that arm 90 is at every instant in position to operate in response to a received signal. As soon as the styluses II and 90, now operating in synchronism, are also in proper phase relation, the system will be in condition for the transmission and reception of visual signals.

Synchronization and phase relation is accomplished by means of the synchronization slow-toenergize magnet 3b which actuates the armature and pawl 3| pivoted at 32 and held against stop 33 by tension spring 34 when the magnet is deenergized. Switch arm 35 is actuated by a proiection on the periphery of synchronization disc II and is capable of closing its right or left contact, thus switching the incoming signal from visual signal responsive magnet 29 to the synchronizlng magnet 30 and vice versa, according to the position in which arm 35 is located.

Assuming that the transmitter is in motion and is scanning the picture appearing on band I shown in Figure 1, each time arm ll reaches its extreme left, an extra long impulse will be transmitted due to the black band 3 appearing in that location throughout the length of the transmitted picture. As explained hereinbefore, the black band is wider than will be obtained at any part of an image being transmitted, these images being usually word images. This results in the transmission of a synchronizing impulse or an impulse of extra long length, the results of which will be described hereinafter.

As the motion of arm ll continues from left to right, and vice versa, the variations of light striking the photoelectric cell I due to the varied intensity of the picture interposed between the source of light and the photoelectric cell will be transformed into electrical impulses which are transmitted by the transmitter and associated equipment.

It will be understood, of course, that the light rays are so directed that no light is impinged on the photoelectric cell except the light beam coming directly toward it at right angles to its plane. Accordingly, in the illustration given, when arm H is directly opposite the dark portion or outline of the figure Y so that the direct light beam normal to the plane of the film I is interposed by a. portion of the figure Y, no light reaches the photoelectric cell, since there are no light beams at any angle other than at right angles.

The result is that as the arm H scans the image, variable amounts of light are impinged on the photoelectric cell. all directly in proportion to the variations in the shades of the image, opposite the image at successive scanned portions of the image. Accordingly, currents varying in accordance with the shade variations flow in the circuit in which the photoelectric cell is connected and these currents are either radiated by modulating a carrier to a receiving station or are transmitted by wire.

Assuming now that motor l3 of Figure 2 is set in motion by closing switch It, said motion will be transmitted through gear l6, shaft H, ratchet 2|, pawl [9, to synchronizing disc l8. This motion will continue in the direction of the arrow until that portion of pawl l9 which extends beyond the periphery of disc M will come in contact with the tongue of pawl 8!, thus disengaging ratchet 2! from synchronizing disc i8. Disc ID will be brought to a stop, in turn stopping hollow shaft 22 and the oscillating motion of arm 24' at the extreme left hand side of the receiving mechanism.

The position of pawl 3| with respect to pawl i9 is such that when pawl l9 engages the tongue of pawl 31, hollow shaft 22' rotates until arm is at its extreme left position ready to sweep to the right. Inasmuch as arms 52' and 24 are driven by motors in substantial synchronism, arm 52 is similarly in its extreme left position for sending a prolonged long or synchronizing impulse.

With arm II on the synchronization band 3, a synchronizing signal is transmitted as previously described. At this time not only is pawl i9 engaged by the tongue of member it, but the projection l8 has engaged the tooth of switch 35 which is sprung to the right (Figures 7 and 8) to engage its alternate contact. Accordingly the synchronizing signal received by the receiver is directed to the circuit including the slow-to-energize magnet which thereupon is energized to actuate armature and pawl 3i. Armature Ii rocks about its pivot 32 against the action of spring 34, disengaging the tongue of member 3| from pawl I9, which will immediately fall into one of the teeth of ratchet wheel 2 I, thus imparting an oscillating motion to receiving arm 24, so that the two arms 52 and 24 are now not only oscillating in synchronism but are also oscillating in proper phase relation in respect to their angular motion.

At the end of each revolution of the receiver synchronization disc I8, the pawl i9 is about to disengage itself from ratchet 2| by striking pawl 3|. However, at this moment and just before such possible disengagement, the transmitting arm II is entering the synchronization band 3, thus transmitting a synchronization impulse, and inasmuch as switch arm is at this time thrown so as to close its right hand contact I ll, due to the pressure of the cam extension IS on the periphery of synchronization disc it it will switch the incoming synchronizing signal into synchronizing magnet 30, allowing the pawl I! to remain in mesh and to continue its rotary motion until transmission ceases.

The stylus 90 which rotates about pivot 25 in order to sweep from right to left over the picture retaining band, is also pivoted at 38 at right angle to its other pivot 25, so that the fork 24 is also permitted to oscillate up and down within the pole pieces 28 of polarized magnet 29.

It is therefore evident that as the receiving stylus 9B oscillates and the picture retainer 26 is moved along, every time arm II in Figure 1 passes over a dark portion of a photograph such as the one shown, it will transmit a. facsimile signal which, when received at the receiving end, will act upon stylus 90 in such a way as to cause the marking end to come in contact with picture retainer 28, thus producing a marking in the same respective location as the dark portion on the transmitted photograph in a manner to be shown hereinafter. I therefore produce a picture identical to the one which is being transmitted but composed of lines closely grouped together, the quality of the picture depending upon the number of these lines per linear inch covered by the scanning arm or the transmitter and receiver.

In the system described above, receiver magnet energizing circuit flows to energize the image receiving magnet 20 or the synchronizing magnet ll only when light is intercepted by a dark spot.

In a modified form or my invention, I contemplate having current flowing in the output of the photoelectric cell to actuate the transmitter, that current flowing to energize the synchronizing magnet 30 or signal magnet 28, as the case may be, when light is impinged on the protoelectric cell. At the receiver, a spring normally tends to operate stylus 90 into engagement with the paper, but is prevented from doing so by the energizing current in magnet 29. When a dark spot of the image is reached at the transmitter, an interruption in the signalling system occurs, resulting in a deenergization of magnet 28 and the consequent operation of stylus Bil against fllm 26 under action of its spring.

If preferred, the spring may be replaced by having the normal position of stylus 93 against film 26 and the energization of the magnet withdrawing the stylus irom the film, as will be understood by those skilled in the art.

Or, if it is preferred to have a negative at the receiver, the stylus may, as in the present case, be operated into engagement with the fllm by energization of the magnet 29, in which case the light portions of the transmitted image will appear as dark portions and vice versa.

In this system, I may use a synchronizing impulse of different amplitude than any image impulse. The band 3 is not needed. Instead I may extend the photoelectric cell 4 beyond the edge of the picture as under the present band I, replacing band 3 with a complete transparency greater than exists at the most transparent portion of the image film I so that when this portion is scanned, an increase in the photoelectric cell output current results in a corresponding increase in the receiver current amplitude. Relay instead of being a slow-to-energize relay is responsive only to currents of this increased amplitude of the synchronizing current. It, therefore, the synchronizing current is received, relay 30 will operate in response thereto.

In another form, this increased synchronizing current may be obtained by terminating the photoelectric cell I just before the portion of strip 3 and placing a second photoelectric cell under present strip 3 more sensitive than cell 4 and therefore having a larger current output than the latter.

In the above I have not attempted to describe the details of the apparatus for carrying out nnr invention.v Figures 1 and 2 are merely schematic circuit diagrams which illustrate in a general way the principles of my invention.

I shall now describe the various parts in detail. In Figure 3 I show a detail drawing of the right hand side elevation of the transmitter. Upon a frame 3'! two uprights 38 are suitably mounted and are so shaped as to support a mandril 39 upon which the picture to be transmitted consisting of a roll ll! is mounted, free to rotate around the mandril 89.

The fllm roll 40 consists preferably of a translucent substance which will permit variable amounts of light to pass through at different points, depending on the picture but may, if preferred, merely consist of a roll on which an image is printed and which reflects varying quantities of light, depending on the image. Roll 40 passes between rollers 4i and 4!, hence over platen l3 and is propelled forward in the direction shown by the arrow by rollers 44 and 45 in a manner to be described hereinafter. Upon the same frame 31 the synchronous motor 2, of any well known construction consisting of a field winding 41', core 48' and armature 49', is shown and is located so that its driving shaft 59', suitably supported in bearingshas secured thereto the worm I rotated by the drive shaft. Worm I is in proper mesh with worm gear 9. Gear 8 is secured to and imparts rotary motion to shaft 9 upon which cam I9 is securely fastened.

Bearing against cam I9 is a cam follower 52' (Figure 4) secured to and driving shaft l2. Coiled about shaft I2 is a spiral spring 53, one end of which is secured to arm 54 and the other end bearing against the bracket 69. Cam follower 52' is thus normally held in engagement with cam III by the action of coil spring 53.

At the other extremity of shaft l2, arm 54, securely connected to the shaft, carries the optical system of the device consisting of a source of light 55 mounted in a light beam reflector or director which limits the beam to light rays in a single direction as shown. These light rays are properly focused by objective lens 56 into a prism 51 which in turn reflects the single pencil of light rays at right angle to photoelectric cell 4 which, together with a portion of the platen 43 and rollers, is shown in cross-section.

Before impinging on the photoelectric cell, the ray of light must first pass through the image containing film and through the slit 43' of platen 43 provided for the purpose. By reason of the construction of reflector 51 and its relative position to the film, all of the light passes at right angles to the film and only through that portion of the film directly opposite the light reflector 51.

The operation of scanning should now be clear. With the armature shaft 59' of motor 2 rotating, worm 1 drives gear 8 to in turn rotate shaft-9 and cam I9.

As cam 19 rotates, cam follower 52' is oscillated back and forth, in turn rocking shaft I2. The source of light 55 and its associated mechanism is correspondingly oscillated, providing a sweeping movement for reflector 51 and thus moving the light beam from point to point on the image from one edge to the opposite edge, scanning a single arc line of the image.

Following the scanning of an arc line of the image, the film is stepped a sufficient distance to present a new arc line for scanning. This will now be described.

The film feeding mechanism comprises disc 59 which is secured and rotatable with shaft 9 and therefore revolves with worm gear 8. Upon disc 59 two pins 60 and BI are secured and as the disc revolves, they come in contact with the projection 52' of arm 62 pivoted at 63. As the pins continue to rotate, they impart a reciprocating motion to connecting link 64 secured at one end to arm 62 and at its opposite end to arm 55. As link 64 reciprocates, it in turn actuates arm 55 upon which pawl 55 is held under tension against a tooth of ratchet 51 by spring 68.

As shown, link 64 has secured thereto the collar 63', and slides in bracket 64' fastened to upright 38. When link 64 is moved to the left in the manner described above, collar 53' compresses the spring 65', interposed between the collar 63' and bracket 54', so that when pin 8| passes beyond and releases arm 62, link 64 is returned to the position shown. Reciprocating motion is thus imparted to link 64, resulting in moving pawl 69 to turn ratchet wheel 61 and then returning the pawl 66 to engage a new tooth.

It will be understood from the description to this that they respectively engage point that the position of pins 89 and Si is such arm 62 when the arm H has been swung to either of its extreme positions and is about to return so that the roll is fed one step and the return of the scanner stylus is effected over an adjacent line to be scanned.

In Figure 4 I show a section through the main shaft 9 of the transmitter mounted in the bearing 69 formed in a bracket 69' and I show in detail worm gear 8 secured to and rotating shaft 9 to which is also secured for rotation therewith cam l0 and paper feed disc 59. In the same figure. finger 52' is shown in its respective location with cam 19.

Figure 6 is a top view of the transmitter with portion of it cut away to show the respective position of the photoelectric cell to the platen and the film.

Upon base 31; the two uprights 38 are securely mounted as at 38'. The roll of film containing the image to be transmitted is also shown at 40 while rollers 42 and 45 are shown in their respective location. The main bearing 69 supports shaft 9 upon which worm gear 8, cam Ill and film feed disc 59 are secured. The scanning arm I I carried by arm 54 is shown in a central position while the optical system, consisting of source of light 55, objective lens 56 and prism 51, is shown mounted thereupon in the proper location.

Under platen 43, a portion of the photoelectric cell 4 is shown together with suitable mounting means. The photoelectric cell 4 is arcuate in shape and is supported at its extreme ends in fittings 59 by means of which circuit connections are madefrom the photoelectric cell to the transmitter; its-shown, a slot 59 permits the narrow faysequal to the thickness of the line to. to impinge upon the photoelectric cell. It 'wlll'be noted that the are covered by the arm 19 is the same. as the arc of the photoelectric cell, so that in every position of the reflector 51, it is opposite a point of the photoelectric cell. The operation of the transmitter is as follows:

When the circuit of the synchronous motor 2 is closed, its armature rotates, which in turn will drive worm I. The worm gear 9, therefore, will rotate in the direction shown by the arrow, carrying with it its cam in, and inasmuch as finger 52' bears against it and is held in that position by spring 53 (Figure 3), it is evident that arm i I will oscillate from left to right at a speed determined by the synchronous motor.

As shaft 9 revolves, pins 69 and GI will come in contact with arm 62 and will rock it in the direction of their motion, carrying with it connecting rod 94 and rocker arm 85 (Figure 3) so as to impart an intermittent rotating motion to ratchet 61, causing the film to advance a predetermined amount.

If the circuit controlling the source of light is closed, a very sharp beam of light will be focused upon the photoelectric cell 4 and as this beam is intercepted by the dark portion of the picture appeering on film 49, a corresponding change will occur in the amplifying circuit to which the photoelectric cell is connected, thus transforming light changes into electrical changes. It is obvious that the entire transmitting unit is to be light tight and therefore a cover H protects the entire unit from external light and dust. This completes the description of the transmitting apparatus and a detailed description of the receiving apparatus with its corresponding parts will now be given,

6 more Figure '1' shows the ht hand side elevation ratchet wheel ill, advancing the paperan amount of thereceiving unit wh l ch consists of a base 12 equaltothatinthetransmitter. Itwillbeunderupon which are mounted a pair of uprights. one stood that the reciprocatingmotion of link "ll of which is shown at 13. A roll of paper II. coatfor oscillation arm I is accomplished by the ed with a substance which is to be described heremovement of arm HM together with the compresinafter, is free to rotate around shaft 18. Said sor M8, in the manner described in detail in paper passes between rollers it and II over platen connection with the transmitter.

is and under feed rollers II and II. A synchro- As a result of pawl is being enmeshed by ratchnous motor I8. similar to the described in detail at wheel 2|, the synchronization disc is will rein connection with the transmitter, is provided volve in the direction indicated by the arrow, and 10 with an armature Ii, which drives the worm it, inasmuch as projection it will not be opposite meshing with gear i which is secured to and switch arm 86, the latter will close its left hand drives shaft l1. Motor I I is in mesh with worm contact ill, deviating all incoming facsimile siggear II by means of worm ll. Shaft I! also carnals' into magnets 29 and 2|, as ditiries a cam 28 identical to cam ll of the transmitcally shown in Figure 1.

ter unit and a synchronisation disc I. which re- It is now evident that facsimile signals received volves in the direction shown by the arrow. while the stylus arm III is sweeping over its As in the case oi the transmitter, cam 23 actuarcuate path, are switched to act upon magnets ates cam follower 21 which is secured to and ro- 2s and 29', and armature 21 will causethe stylus tates the shaft 25. Secured b0 and rotatable with to move up and down about pivot I. bring-[n tho shaft is arm It. A spring ll. one end of which marking mt a: in t t mm th specially engages the arm ll. the other end of which entreated paper passing over platen n.

8 8% h n r a y holds e 111 the stylus is in a position corresponding to the follower ll ag in m 1 wn in fl position of the transmitter scanner Ii, and the imparting 0 Shaft 25 and to m n 1 signals of the proper amplitude and timing, they 25 let 'y m i n when! Wi h that of m II will produce markings upon the specially treated at the transmitter. :The arm l 0817188 in its mopaper at a, corresponding portion thereon of 3 tion the stylus 90 which is pivoted at it for a seclength e ual to the image at that point, thus our! rocking m v m n o n 1101!! the D1360 reproducing the original picture in the form of the paper H. dashes closely grouped together, which will form 30 At one end of the stylus ll, a suitable marker an image slmuar t th one t tt 93 is fastened into retainer I while at the other In Figure 9 1 Show t left h elevation of end an iron sment 21 passes be wee the Poles the receiver where a clear understanding oi the of a polarized masne I w Win41!!! is shown respective position of synchronous motor It,

at 29 and 20'. Figure 8 is a detailed view or the worm It and worm gear it may be seen.

ynchronization mechanism and it is shown in I have cut a portion of the worm gear II in the position which the Whine l 1 11 when order to show follower ll bearing against cam 28.

the transmitter ceases to fun i n at the In order to secure a positive motion of the mi ns endor the sake of mplicity. in cture sensitized paper 1 the rollers II and so are posi- 8 the worm II and the w rm 8 1 are not tively drawn by pinions H6 and ill, the latter shown. Upon the ame sc P p r f d pins I" being mounted in rotatable relation with the K are diametrically l ca d so as to sur every shaft m which carries ratchet wheel m.

revolution an arm III which in turn feeds the pa- In figure m 1 Show t view of th complete per out bym ansoi'c nnec insrod llll ckeri". receiver. The stylus so is shown in a central pawl 01 and ra che w l r reierrlns to position and the dotted lines indicate the maxilsure .11 ill e noted that 88 800B 88 the mmum swing from side to side. It will be noted chroni e ion ma net llisen 's zedi i that thismember is forked at one end 24' in 3|, pivoted at 32. will releflte W Whmh in order to accommodate armature 2! to which it is turn und r con rol 1' o e ll will move secured by rivets m and m. tooth to engage a o h 1' 'fl Wheel As the stylus arm 90 sweeps over the sensitized b91118 fas n d t hort I7. is revolving n the paper II, armature 21 will oscillate between the rection shown by the arrow. pole pieces of the polarized magnet 2|. Inas- It is to be understood a in h receiver hmuch as stylus arm at is also pivoted at as and anism, synchronization disc II is not secured to 1 free to move in an upward and downward shaft but by a s of ahollow shaft "J motion, it is evident that any signal received by shown in Figure 8- mar similar in length to the one appearing in In he am ls re 8, n la s limitation the :13? to of the transmitter. I8 is secured a h p p y of n ll- This sensitized paper may be wax covered, cartion disc ll, causing switch arm 38 to close either boned, photograplflc light sensitive, chemically its right or left hand contact Ill and I ll respectreated, or any other well lmown type, and I do tively. In Fisure 8 the ight and side n ac not wish to be restricted by the type to be used. ii. is closed and by ref ring to i it l When a record is made on carbon, waxed paper be noted that the first impulse that will be reand the like, provision is made for rendering the ceived will be switched to magnet ll, thus releasrecord immediately visible. This I accomplish ing pawl l9 and causing stylus III to oscillate over by the transparent glass window ill placed in the specially prepared paper. It is to be noted the receptacle, so that an observer can imthat one of the pins I03 serves as the pivotal supmediately see the record. port for the pawl it on synchronization disc II. In order to simplify the operation of reading This is better shown on Figure 12 and it is therethe sensitized paper under the various rollers, I fore evident that at each half revolution of synhave provided a knob at III! which may be rechronization disc ll, arm "M will be acted upon. volved by hand, thus causing any amount of thus imparting an intermittent rotating motion to paper to be drawn from the paper supp y.

Figure 11 is a section taken at II-I I on Figure 9. In this drawing I show the section through the uprights I3 and I3 supporting the platen 18 over which the sensitized paper II is carried forward by rollers I8 and 88, moved together by plnions H8 and III.

Figure 12 is a cross section through the main shaft II of the receiver. Upon this shaft the worm gear I8 and the ratchet wheel 2I are secured and the entire assembly rotates in bearing I22 formed on bracket I23.

A hollow shaft 22 rotates freely around main shaft II and has keyed thereon at one end the receiving cam 23 and the synchronous disc I8 at the other.

Figure 13 is a detailed drawing of the receiver cam 23 which is identical to Figure showing the transmitting cam I8.

Figure 14 is a detailed view of the rear of the synchronization disc l8 showing the switch actuating projection I8, securely fastened to it, by means of screws I21 and located so that it projects beyond the periphery of the disc itself. a

Figure 15 is an assembly drawing 01' the single phase synchronous motor which I prefer to use. This motor consists of a coil I28 mounted over a core I29 substantially of the design shown in this figure. A non-magnetic bridge I38 is secured to the core I28 by means of screws I3I and forming at I82 a bearing for the motor shaft I33.

While I show a simplified form of synchronous motor, it is understood that one employing a self starting principle such as single phase motors employing shading coils may be used, provided they do maintain a constant synchronous speed it not over-loaded.

Figure 16 is a modification of my invention to make possible a reception of half tone photographs. In this figure I only show that portion of the receiver which needs to be modified, while the other portion of mechanism remains unaltered.

In this modification I substitute the stylus 88 of the receivers mechanism with a similar member I34 substantially capable of being shaped as shown.

I also eliminate the receiving polarized magnet 28 and substitute an optical system substantially similar to the one shown in Figure 3 and consisting of sources of light I35 focused by an objective lens I36 upon prism I31, bending the light 88 degrees and focusing it upon the light sensitive paper I38 supplied in roll form at I39. After the paper has been exposed, it is fed forward by the same mechanism previously described and the exposed sensitized paper is allowed to accumulate in roll form over take-up roller I48 pivoted at I", or may first be passed through a developer and fixer, and then through a drier, after which it is permitted to accumulate on rolls. A groove pulley I42, secured to the paper feed shaft I48, is connected to the take-up groove pulley I, secured to take-up roller shaft Ill, by means of spring belt I45 which tends to rotate the take-up roller faster than the paper is expelled, thus keeping the paper I38 always taut. The entire receiving mechanism is protected by light-proof casing I45 which protects the device from extraneous sources of light, dust and grit.

If the paper I38 is coated with a substance which is affected by light proportionate to its intensity, any variaticn of light intensity of source of light I35 will correspondingly produce a variation of intensity of the light beam which strikes the sensitized paper, thus producing an image identical to the one transmitted by the transmitter.

In Figure 17 I show another modification of my invention in which the stylus 88 is substituted by a pointer I45 constantly lightly bearing upon a specially treated paper I88.

The pointer I 81 is electrically insulated from the machine by suitable means and is connected to one side of the circuit while the other is grounded to the frame of the machine.

Paper impregnated with a solution of various salts has the property of discoloring when interposed between two differing polarities of an electrical circuit and I use this principle to record images by utilizing a paper so treated and interpose it between the pointer I" and frame I88.

In the receiver described hereinbefore, the receiver stylus moved in an are over a fiat sheet. In the modification shown in Figures 18 and 19, while the angular motion of the stylus is maintained, linear scanning of the picture is obtained in a straight line across the transmitter and the receiver picture, the sheet being arced as distinguished from the fiat sheet described hereinbefore.

The marking power is supplied by a dynamic unit which makes it possible to connect the receiver in place of the present loud speaker in a radio receiver as generally found in the average home.

In this modification, the finger 28 is actuated by cam 23 and oscillates shaft 288. Shaft 288 oscillates in bearings 284 and carries at one end an arm 285. Anchored to arm 285 by suitable means at 288 and 289, the resilient stylus supports 288 and 281 are in flexible connection with the stylus.

As the shaft is oscillated, the arm 285 rocks back and forth carrying with it the stylus arm H I which moves in an are, as shown in Figure 19.

The oscillatory movement of shaft 288 is also transmitted to the moving coil "I of the electrodynamlc motor 282, having windings 283.

Moving coil 28I is securely fastened to the oscillating shaft 288 by a screw 2 I3 which holds the coil in place. However, it permits coil 28I to move up and down in response to received signals, due to the resilient membrane 2 I 4, so shaped as to obtain the motion of the coil 28I. This motion by means of a spider frame 2 I5 is transmitted to the bell crank 2I8, pivoted at 2". The bell crank 2II is at one end secured to the stylus 2H carrying at its extremity the pointer 2I8.

The winding of coil 283 is energized by the direct continuous current available in the ordinary radio receiver. The moving coils 28I are connected to the output of the last tube. When new a signal is received causing the moving coil 28I to oscillate in and out of the magnetic field of coil 283, it will cause stylus 2| I to oscillate in such a manner as to come in contact with the paper 2I2 and produce an image similar to the one transmitted, with any of the methods previously described. To limit the motion of these members 286 and 281, I have provided the screw adjustment 2I8, which prevents stylus 2 from digging into the paper 2I2 as the picture is being recorded.

In Figures 28 to 22 I have disclosed a method of mounting my vision recorder on an airplane.

In Figure the receiving instrument 388 is mounted on the instrument board 38I of the airplane 382. As shown in Figure 21, an opening 38I is provided in the instrument board 38I in which the instrument 388 is set. Secured to the instrument board III by bolts I is a casing III which provides a support for the instrument board through the compression springs III! which are riveted at one end to the casing ill by rivets I06 and are mounted at its other end in the bearing caps 301.

At the rear of the instrument I have provided tension springs III with the anchors Sill and ill.

As shown in Figure 22 hand holds III are provided in the casing I03 to enable the mounting of the springs "I. Tension springs III are also provided for preventing upward movement, the tension springs ill being mounted in the anchors 3|! and ill. A hand hold Ill enables the mounting of the springs us. By this arrangement the shocks and jars to which the airplane is subjected are not transmitted to the instrument which in effect floats in position by reason of the several spring mountings.

Although I have illustrated my invention as applied to the general transmission of vision, I also intend it for other uses to which it is especially adapted. Thus, for example, my invention contemplates operating the switch 320 from a radio receiver to the facsimile system shown in Figure 2. with this arrangement the owner .of a radio receiver of the standard type may switch from the reception of ordinary broadcasts to the reception of vision for the purpose of obtaining visual record of the broadcasting station.

In another form my invention contemplates enabling the owner of a radio receiver to switch his receiver to the visual recorder for operation during the interval to receive illustrated news bulletins.

It will be obvious from this that my invention may take several forms and I do not wish to be limited except as set forth in the appended claims.

I claim:

1. A facsimile system having a transmitter; a receiver: a facsimile signaling channel connecting said transmitter and receiver; continuous synchronous positive driving means at said transmitter and receiver; a positive drive connecting means between said driving means and said receiver; means for disconnecting said drive connecting means from between said driving means and said receiver for rendering said driving means and said receiver non-efi'ective; and means operative in the event the receiver is in synchronism with said transmitter for preventing said disconnecting means from operating.

2. A facsimile system having a transmitter: a receiver; a facsimile signalling channel connecting said transmitter and receiver; continuous synchronous positive driving means at said transmitter and receiver; a positive drive connecting means between said driving means and said receiver; means for disconnecting said drive connecting means from between said driving means and said receiver for rendering said driving means at said receiver non-efi'ective and for simultaneously preparing to render itself nonoperative in the event that said transmitter and receiver are in synchronism.

3. In a facsimile system: a transmitter, a receiver; a signalling circuit connecting said transmitter and receiver; a positive drive for said receiver facsimile and synchronizing apparatus at said receiver; switching means at said receiver for separately switching said facsimile and synchronizing apparatus to said signalling circuit: and means whereby when said synchronizing apparatus is connected to said signalling circuit, said facsimile apparatus and drive therefor are system; a receiver comprising a pivoted arm: a rotatable motor; means for translating the rotation of said motor into a reciprocating motion for rocking said arm about its pivot in a reciprocating movement for line for line scanning; a second pivot at right angles to said first pivot; and means responsive to received facsimile signals for rocking said arm about said second pivot.

5. In a facsimile system; a receiver having an arm; a pivot for said arm; a rotating motor; a cam; means including said cam for translating the rotary motion of said motor into oscillating motion for rocking said arm in a reciprocating motion about its pivot; an image carrying film over which said arm sweeps in its movement for scanning an image: and means whereby said motor feeds said film a single step following each complete sweep of said arm whereby said arm scans a new line, and means for rocking said arm transversely to said reciprocating motion into and out of engagement with said film in response to received impulse bonditlons.

6. In a visual signalling system, a receiver comprising a movable coil unit, a central axis on which said coil is mounted for rotation thereabout, a field of substantially constant magnetic intensity, means responsive to received picture signalling currents for energizing said cell to operate it in said field of constant magnetic intencity, a scanner mounted on said axis for rotation thereabout in synchonism with the received picture signals and means on said scanner controlled by said movable unit for recording an image in accordance with the said picture signals.

7. In a visual signalling system, a receiver comprising a movable coil, a central axis on which said coil is mounted for rotation thereabout. means for energizing said cell in accordance with received picture signals, a scanner mounted on said axis for rotation thereabout in eynchonism with the received picture signals and picture recording means controlled by said coil for producing a record in accordance with the received picture signals.

8 In a visual signalling system, a receiver comprising an electron amplifier. a source of power for operating said amplifier, a floating coil connected to said amplifier. a central axis on which said coil is mounted for rotation thereabout, a magnetic field energized by said source of power, a scanner mounted on said axis for rotation thereabout in synchonism with the received picture signals and circuit means for connecting said floating coil to the output of said amplified whereby said scanner is controlled by received picture signals energizing said electron amplifier gag variably operating said floating coil in said' 9. In a visual signalling system, a receiver comprising a stationary winding for generating a magnetic field, a movable winding operable in a magnetic field produced by said first winding, a central axis on which said movable winding is mounted for rotation thereabout. a scanner mounted on said axis for rotation thereabout in synchronism with the received picture signals, means for energizing said movable winding in accordance with received picture signals, and means controlled by said movable winding for recording an image in accordance with the operation of said movable winding by said received picture signals 4. In afacsimile 10. Inavisualsignalling system,areceiver comprising a stationary winding tor generating a magnetic field, a movable winding operable in the magnetic field produced by said first winding means for energizing said movable winding in accordance with received picture signals, a central axis on which said movable winding is mounted for rotation thereabout, a scanner mounted on said axis for rotation thereabout in synchronism with the received picture signals, and means on said scanner controlled by said movable winding tor recording an image in accordance with the operation of said movable winding by said received picture signals, said last means comprising a stylus and.mechanical connection from said movable winding to said stylus.

11. In a visual signalling system, a fixed winding having a central opening, a shaft extending through said central opening, a movable winding, a supporting means connected to said shaft and secured to said movable winding whereby said movable winding is supported for movement with respect to said first winding, a stylus, a mechanical connection from said movable winding to said stylus, means controlled by said shaft for operating said stylus to scan in synchronism with the received picture signals and means for energizing said movable winding in accordance with received picture signals for vibrating said movable winding with respect to said first winding and producing a corresponding vibration of said stylus.

12. In a visual signalling system, a fixed winding having a central opening, a shaft extending through said central opening, a movable winding. a supporting means connected to said shaft and secured to said movable winding whereby said movable winding is supported for movement with respect to said first winding, a record controlling means mounted for rotation about said shaft, means for operating said record controlling means in synchronism with the received picture signals, a mechanical connection from said movable winding to said record controlling means, and means for energizing said movable winding in accordance with received picture signals for vibrating said movable winding with respect to said first winding and producing a corresponding operation of said record controlling means.

13. In a visual signalling system, a. fixed winding having a central opening, a. shaft extending through said opening, a movable winding, a supporting means connected to said shaft and secured to said movable winding whereby said movable winding is supported for movement with respect to said first winding, a stylus, a mechanical connection from said movable winding to said stylus, and means for energizing said movable winding in accordance with received picture signals for vibrating said movable winding with respect to said first winding and producing a corresponding vibration of said stylus, a second mechanical connection from said shaft to said stylus, means for rocking said shaft whereby the stylus is operated in a reciprocating motion about said shaft, and a recording chart in operating relation with said stylus.

14. In a visual signalling system, a receiver comprising a mechanical movable stylus, a recording chart in the form of an are, means for moving said stylus across said chart in a plane normal to the recording chart, means for moving said stylus in accordance with received picture signals for producing corresponding records on said chart, and means whereby said stylus is moved over adjacent lines of said chart successively.

15. In a visual signalling system, a receiver comprising a mechanical stylus, a recording chart in the form Man are, means for moving said stylus across said chart in a plane normal to the recording chart, means comprising a magnetic coil operable in a constant magnetic field in response to received picture signals for mechanically moving said stylus in accordance with received picture signals for producing corresponding records on said chart, and means whereby said stylus is moved over adjacent lines of said chart successively.

16. In a visual signalling system, a receiver comprising a mechanical stylus, a recording chart in the form of an are, means for moving said stylus in a plane normal to the recording chart across said chart, means comprising a magnetic coil operable in a constant magnetic held in response to received picture signals for operating said stylus along its longitudinal direction in accordance with received picture signals for producing corresponding records on said chart, and means whereby said stylus is moved over adjacent lines of said chart successively.

17. In a visual indicator system, a transmitter, a receiver, synchronous motor means at said transmitter and receiver, positive drive connections from said motors to their respective transmitter and receiver for operating said transmitter and receiver in substantial synchronism with each other, means at said transmitter for generating picture signals in accordance with a record thereat, means at said receiver responsive to said picture signals for reproducing a record of said transmitter record, means at said transmitter for transmitting periodic synchronizing impulses, means at said receiver responsive to said synchronizing impulses for controlling the positive drive connection or release of said receiver from its synchronous motor.

18. In a visual indicator system, a transmitter, a receiver, synchronous motor means at said transmitter and receiver for operating said transmitter and receiver in substantial synchronism with each other, a positive driving connection from the synchronous motor of said receiver and its associated receiver apparatus whereby said receiver is driven positively from said synchronousmotor,means at said transmitter for generating picture signals in accordance with a record thereat, means at said receiver responsive to said picture signals for reproducing a record of said transmitter record, means at said transmitter for transmitting periodic synchronizing impulses, means at said receiver responsive to said synchronizlng impulses for controlling the connection or release of said receiver from said synchronous motor.

19. In a visual indicator system, a transmitter, a receiver, synchronous motor means at said transmitter and receiver; a positive drive connection from said motor means to said receiver for positive driving of said transmitter and receiver in substantial synchronism with each other, means at said transmitter for generating picture signals in accordance with a record thereat, means comprising a magnetic coil operable in a fixed magnetic field at said receiver responsive to said picture signals for reproducing a record of said transmitter record, means at said transmitter for transmitting periodic synchronizing impulses, means at said receiver responsive to said synchronizing impulses for controlling the positive drive connection or release of said receiver from said synchronous motor.

20. In a visual indicator system, a transmitter, a receiver, synchronous motor means at said transmitter and receiver; a positive drive connection from said motor means to said receiver for positive driving of said transmitter and receiver in substantial synchronism with each other, means at said transmitter for generating picture signals in accordance with a record thereat, means comprising a magentic coil operable in a fixed magnetic field, a stylus controlled by said magnetic coil at said receiver responsive to said picture signals for reproducing a record of said transmitter record, means at said transmitter for transmitting periodic synchronizing impulses, means at said receiver responsive to said synchronizing impulses for controlling the positive drive connection or release of said receiver from said synchronous motor.

21. In a visual indicator system, a transmitter, a receiver, synchronous motor means at said transmitter and receiver, a positive drive connection from said motor means to said receiver for positive driving of said transmitter and receiver in substantial synchronism with each other, means at said transmitter for generating picture signals in accordance with a record thereat, means comprising a magnetic coil operable in a fixed magnetic field, a stylus controlled by said magnetic coil in a longitudinal direction at said receiver responsive to said picture signals for re producing a record of said transmitter record, means at said transmitter for transmitting periodic synchronizing impulses, means at said receiver responsive to said synchronizing impulses for controlling the positive drive connection or release of said receiver from said synchronous motor.

22. In a visual indicator system, a transmitter, a receiver, synchronous motor means at said transmitter and receiver, a positive drive connection from its associated motor to said receiver for operating said transmitter and receiver in substantial synchronism with each other, means at said transmitter for generating picture signals in accordance with a record thereat, means comprising a magnetic coil operable in a fixed magnetic field, a stylus controlled by said magnetic coil in a longitudinal direction and operable across a chart in straight lines at said receiver responsive to said picture signals for reproducing a record of said transmitter record, means at said transmitter for transmitting periodic synchronizing impulses, means at said receiver responsive to said synchronizing impulses for controlling the positive drive connection or release of said receiver from said synchronous motor.

23. In a visual indicator system, a transmitter, a receiver, synchronous motor means at said transmitter and receiver, a positive drive connection from its associated motor to said receiver for operating said transmitter and receiver in substantial synchronisrn with each other, means at said transmitter for generating picture signals in accordance with a record thereat, means comprising a magnetic coil operable in a fixed magnetic field, a stylus controlled by said magnetic coil in a longitudinal direction and operable across an arcuate chart in straight lines at said receiver responsive to said picture signals for reproducing a record of said transmitter record, means at said transmitter for transmiting periodic synchronizing impulses, means at said receiver responsive to said synchronizing impulses for the positive drive controlling the connection or release of said receiver from said synchronous motor.

24. A facsimile system having a transmitter, a receiver, a facsimile signalling channel connecting said transmitter and receiver, a motor drive for said transmitter, a motor drive for said receiver, a positive drive connections means between said receiver motor drive and said receiver, means for disconnecting said positive drive connection from between said receiver motor drive and said receiver for rendering said receiver inoperative, and means operative in the event the receiver is in synchronism with the said transmitter for preventing said disconnecting means from operating.

25. A facsimile system having a transmitter. a receiver, a facsimile signalling channel connecting said transmitter and receiver. a motor drive for said transmitter, a motor drive for said receiver, a positive drive connection means between said receiver motor drive and said receiver. means for disconnecting said positive drive connection from between said receiver motor drive and said receiver for rendering said receiver motor inefiective in driving said receiver and for simultaneously preparing to render itself nonoperative in the event that said transmitter and receiver are in synchronism.

26. In a facsimile system; a receiver comprising a pivoted arm; a rotatable motor; means including a cam driven by said motor and a follower for said cam secured to and driving said pivoted arm for translating the rotation of said motor into a reciprocating motion for rocking said am about its pivot in a reciprocating movement for line for line scanning; and means responsive to received facsimile signals for rocking said arm in response to received impulses for making a record.

27. In a facsimile system; a receiver comprising a pivoted arm; a rotatable motor; means including a cam driven by said motor and a follower for said cam secured to and driving said pivoted arm for translating the rotation of said motor into a reciprocating motion for rocking said arm about its pivot in a reciprocating movement for line for line scanning: and means responsive to received facsimile signals for rocking said arm in response to received impulses for making a record; a positive drive connection from said motor to said cam and means responsive to synchronizing signals for controlling the connection of said positive drive.

28. A signalling system having a transmitter; a receiver; a signalling channel connecting said transmitter and receiver; a motor drive for said transmitter; a motor drive for said receiver; a positive drive connection means between said receiver motor drive and said receiver; periodic means for disconnecting said positive drive connection from between said receiver motor drive and said receiver for rendering said receiver inoperative, and means operative in the event the receiver is in synchronism with the said transmitter for preventing said disconnecting means from operating.

29. A signalling system having a transmitter: a receiver; a facsimile signalling channel connecting said transmitter and receiver: a motor drive for said transmitter; a motor drive for said receiver; a positive drive connection means between said receiver motor drive and said receiver; means at said transmitter for periodically sending out a synchronizing signal over said signalling channel and means at said receiver responsive to said synchronizing signal and rendered nonooer- 

